; WITH Dates
AS
(
	-- This would be equivalent to 20 years from year 2000
	SELECT	DATEADD( d, number, '01-Jan-2000' ) as Date
	FROM	(
				SELECT	TOP 10000 ROW_NUMBER() OVER( ORDER BY ( SELECT 1 ) ) AS Number
				FROM	master.sys.columns c1
						cross join master.sys.columns c2
			) n
	WHERE	DATEADD( d, Number, '01-Jan-2000' ) < '31-Dec-2020'
)
SELECT	*
FROM	Interval I
		CROSS APPLY Dates D
WHERE	I.IntervalType = 'Year'
		AND 
		(
			DATEADD( DAY, DATEDIFF( DAY, 0, I.IntervalStart ), 0 ) = D.Date 
			OR DATEADD( DAY, DATEDIFF( DAY, 0, I.IntervalEnd ), 0 ) = D.Date
			OR 
			(
				DAY( I.IntervalStart ) = DAY( D.Date )
				AND MONTH( I.IntervalStart ) = MONTH( D.Date )
			)
		)
		AND D.Date >= I.IntervalStart
		AND D.Date <= I.IntervalEnd